2 research outputs found
Enhanced Electrorheological Performance of Nb-Doped TiO<sub>2</sub> Microspheres Based Suspensions and Their Behavior Characteristics in Low-Frequency Dielectric Spectroscopy
Titanium dioxide and Nb-doped titanium
dioxide microspheres with the same size were fabricated by a simple
sol–gel method, and the formation mechanism of Nb-doped titanium
dioxide microspheres was proposed. Titanium dioxide and Nb-doped titanium
dioxide microspheres were adopted as dispersed materials for electrorheological
(ER) fluids to investigate the influence of the charge increase introduced
by Nb doping on the ER activity. The results showed that Nb doping
could effectively enhance the ER performance. Combining with the analysis
of dielectric spectroscopy, it was found that the interface polarization
of Nb-doped TiO<sub>2</sub> ER fluid was larger than that of TiO<sub>2</sub> ER fluid, which might be caused by more surface charges in
Nb-TiO<sub>2</sub> microspheres due to Nb<sup>5+</sup> doping and
resulting in enhancement of electric field force and strengthening
of fibrous structure. In addition, by comparing and analyzing the
permittivity curves of Nb-TiO<sub>2</sub>/LDPE solid composite and
Nb-TiO<sub>2</sub>/silicone-oil fluid composite, it could be concluded
that the enhancement of permittivity at low frequency resulted from
the increase of the order degree of dispersed particles in ER fluid
rather than from the quasi-dc (QDC) behavior. Moreover, the absolute
value of slope of permittivity curves (<i>K</i>) at 0.01
Hz could be utilized as the standard for judging the ability to maintain
the chainlike structure. The relationships between polarizability
of dispersed particles, dielectric spectrum, parameter <i>K</i>, and ER properties were discussed in detail
Intercalation Synthesis of Prussian Blue Analogue Nanocone and Their Conversion into Fe-Doped Co<sub><i>x</i></sub>P Nanocone for Enhanced Hydrogen Evolution
Compared with the
monometallic phosphides, bimetallic phosphides
can further improve the catalytic performance for hydrogen evolution
reaction (HER). As such, the rational design and facile synthesis
of bimetallic-based phosphides with well-controlled architectures
and compositions is of scientific and technological importance. In
this work, Fe–Co Prussian blue analogue (PBA) nanocones (NCs)
have been successfully fabricated via an intercalation reaction strategy
by utilizing layer structured α-CoÂ(OH)<sub>2</sub> NCs as self-sacrificing
templates. After calcination and phosphorization process, Fe–Co
PBA NCs can be converted to Fe-doped Co<sub><i>x</i></sub>P NCs without obvious shrinkage. Electrochemical tests show that
Fe incorporation can effectively promote the electrocatalytic activities
of Co<sub><i>x</i></sub>P. This simple and effective method
will be of benefit for the development of other functional Co-based
bimetallic compounds. Furthermore, this strategy can possibly be extended
to fabricate a series of PBA materials with special structure and
novel morphology, which can serve as a promising platform for diverse
applications, especially in energy storage and conversion